Yeah, I have the same problem with my lecturers. They only teach me material that I didn’t realise I already know. 
But seriously, Castaneda sounds like he has some interesting and valuable work (taken with a grain of salt), I’ll have to check it out.
The problem with Castaneda is that his “mythology” is very dark. Most of the LD’ers I know who have read his books have had awful lucid nightmares. Moreover, as I’ve said above, it’s not sure he had understood Don Juan Matus’ teachings (if there was a Don Juan Matus). And he’s never said his books were a general, valid for everybody, method. He said they were only the teachings he received from Don Juan Matus, and these teachings may be presented in a form that could be valid only for him. And it could be the case, since another Don Juan’s apprentice (La Gorda) seems to have received different teachings about dreaming, as I pointed it out in a post above.
That’s why I would advice to take a step back when reading his books, especially concerning the dream subject.